Semiconductor device having electrostatic protection circuit and method of fabricating the same

摘要

A semiconductor device including an electrostatic protection circuit capable of preventing current from being concentrated in a hot spot through a silicide layer. A plurality of salicide N-type MOS transistors isolated by a first diffusion region are formed on a semiconductor substrate of this semiconductor device. An NPN lateral bipolar transistor and a Zener diode are formed as an electrostatic protection circuit for these MOS transistors. The NPN lateral bipolar transistor includes a P-type well and a second diffusion region which is formed in a region isolated by two second isolation regions. The Zener diode is formed by the PN junction between the first diffusion region of the MOS transistor and a third diffusion region. The breakdown start voltage of the Zener diode is set to be lower than the breakdown start voltage of the MOS transistor. A fourth diffusion region which makes up a Schottky diode together with the silicide layer is further provided between the silicide layer and the third diffusion region.